Indexing turret

ABSTRACT

A tool turret mounted for rotation about and axial movement with a threaded sleeve carried by a base. The freely rotatable turret is selectively locked to the base by a locknut carried by the base and threadingly engaging the sleeve which axially displaces the tool turret to urge curvic couplings fixed to the turret and the base into locking engagement. The turret is rotated or indexed by a rack and a gear fixed to the turret for axial and rotary movement therewith. The gear and rack both have segmented teeth with the segments axially spaced so they disengage when the turret is locked and become engaged to index the turret only when it is axially displaced to unlock the curvic couplings.

Unite States Patent Primary Examiner-William F. O'Dea AssistantExaminer-F. D. Shoemaker A ttomey-Barnes, Kisselle, Raisch & ChoateABSTRACT: A tool turret mounted for rotation about and axial movementwith a threaded sleeve carried by a base. The freely rotatable turret isselectively locked to the base by a locknut carried by the base andthreadingly engaging the sleeve which axially displaces the tool turretto urge curvic couplings fixed to the turret and the base into lockingengagement. The turret is rotated or indexed by a rack and a gear fixedto the turret for axial and rotary movement therewith. The gear and rackboth have segmented teeth with the segments axially spaced so theydisengage when the turret is locked and become engaged to index theturret only when it is PATENTEDUEB21 m?! SHEET 1 OF 6 INVENTORS QQNALDD. CHDPE FRANK A.HEVONKQSKI ATTORNEYS slezadoo PATENTED D5621 I97! SHEET2 OF 6 INVENTORS RONALD D. CHOPE FRANK A. HEVONKO'SKQ Fan-Z ATTORNEYSPATENIED [115221 I97] SHEET 3 [1F 6 IN VENTORS RONALD D. CHOPE FRANK A0HEVONKOSKI ATTORNEYS PATENTEU [JEBZ] {9H SHEET [1F 6 RONALD D. HOPEFRANK Ac HEVOMKOSM ATTORNEYS PATENIEB BEBE] I97! SHEET 5 UF 6 INVENTORSgem-v.0 D. CHOPE BXBANK A. HEVIONKOSK! ATTORNEYS PATENTEU M1321 [9713523400 SHEET 5 [IF 6 INVENTORS RONALD D. CHOPE FRANK A. HEVON K08 KlATTORNEYS INDEXING "runner This invention relates to indexing turretsand more particularly to an automatic turret for machine tools such asvertical lathes and the like.

In this invention a curvic coupling is attached to a tool turretconnected to a threaded sleeve for free rotation about the axis of thesleeve. A second curvic coupling is fixed to a base and positioned tounderlie the first coupling and a nut engages the sleeve and bears onthe base. Rotation of the nut in one direction urges the curviccouplings into locking engagement and rotation in the other directiondisengages the curvic couplings so that the tool turret can be rotatedwith respect to the base. A shaft is fixed at one end to the tool turretand extends axially through the sleeve with a fluted gear fixed to theother end. A fluted rack cooperates with the gear so that the toolturret can be rotated in either direction by movement of the rack onlywhen the curvic couplings are unlocked or disengaged.

Drawings illustrating an embodiment and the features of this inventionaccompany this disclosure and are briefly described as:

FIG. I, an end view of an indexing turret constructed in accordance withthis invention mounted on the ways of a vertical turret lathe.

FIG. 2, a fragmentary end view partially in section of the indexingturret of FIG. 1.

FIG. 3, a sectional view on line 3-3 of FIG. 2 illustrating therelationship of some of the component parts with the tool turret in thelocked position.

FIG. 4, a fragmentary view partially in section similar to FIG. 3illustrating the tool turret in the unlocked position.

FIGS. 5 and 6, plan views of the tool turret and base curvic couplingsrespectively.

FIG. 7, a fragmentary view partially in section on line 7-7 of FIG. 2illustrating in solid and phantom lines the positions of the actuatingbar when the tool turret is locked and unlocked respectively.

FIG. 8, a fragmentary sectional view on line 6-6 of FIG. 2 illustratingthe disengagement of the tooth segments of the gear and rack when thetool turret is in the locked position.

FIG. 9, a fragmentary sectional view similar to FIG. 8 illustrating theengagement of the tooth segments of the gear and rack when the toolturret is in the unlocked position.

FIG. 10, a fragmentary view of the teeth of the curvic couplingsillustrated in solid and phantom lines the locked and unlocked positionsrespectively of the curvic couplings.

Referring to the drawings:

FIGS. I and 2 illustrate an indexing turret 10 on a vertical turretlathef'lhe lathe has a carriage l2 movably mounted on ways 14 with across slide 16. Cross slide 16 carries and provides a base for indexingturret 10.

As shown in FIGS. 3 and 4, indexing turret 10 has a tool turret 18 withrecesses 20 and holders 22 adapted to receive and secure tools 24 to theturret. A curvic coupling 26 is secured by keys 26 and capscrews 30 tothe inner face of tool turret 16 and is engageable with a mating curviccoupling 32 secured in a circular recess 34 in the outer surface of baseslide 116 by keys 36 and capscrews 38. A threaded bolt member or sleeve40 with a ring 42 on one end is connected to tool turret 18 byentrapping ring 42 within a reentrant circular groove formed by thecooperation of curvic coupling 26 with a circular recess 43 in the innerface of tool turret 18. There is a slight clearance between ring 42 andthe reentrant groove so tool turret 18 can rotate freely about sleeve40. A threaded locking member or nut 44 with a flange 45 bearing on ashoulder 46 of base slide 16 engages threaded sleeve 40 to urge curviccouplings 26 and 32 into locking engagement. A plug body 48 attached toand engaging in a recess 49 in the inner face of base slide 116 providesa surface for nut 44 to bear on so that it can axially displace sleeve40 to unlock curvic couplings 26, 32. Preferably, the threads of sleeve40 have a double lead to increase the displacement of the sleeve perrevolution of nut 44.

A central shaft 50 extends axially through sleeve 40 and is journaledfor free rotation therein by bronze bushings 52. Shaft 50 has an endplate 54 with two keyways 56 at right angles to each other and is fixedto tool turret 18 by capscrews 56 and four keys 60 engaging incorresponding keyways 62 in turret 16. The other end of shaft 50 isjournaled in a bronze bushing 64 carried by plug 46 and has a gear 66splined thereto and axially fixed thereon by entrapment between abushing 65 bearing on a shoulder 67 and a nut 68 keyed against rotationby a pin 70. To prevent the sleeve 40 from rotating with locknut 44, aguide pin '72 is held in plug 48 by a setscrew 74 and slidably engagesin a blind hole 76 in the sleeve. Preferably hole 76 is put in sleeve 40when turret 10 is assembled to simplify locating the hole and avoidalignment problems. A dust seal to protect the curvic couplings fromcontamination is provided by a ring 75 fastened to base slide 16 andhaving a circular ridge 77 extending into a circular groove 79 in theinner face of tool turret 18. As shown in FIG. 4, the height of ridge 77and depth of groove 79 are such that they remain engaged when toolturret 18 is unlocked.

As shown in FIGS. 5. 6 and 10, curvic couplings 26 and 32 are annularrings or racks with radially extending and circumferentially spacedcomplementary or mating teeth 78 and 80. The spaced teeth of curviccouplings 26 and 32 provide a plurality of detents and cooperatingsockets so that when the couplings are urged together so the teeth meshthey interleave in locking engagement so the couplings cannot be rotatedwith respect to each other. Preferably each curvic coupling has an equalnumber of teeth and the number of teeth in each coupling is selected sothat they are properly aligned for locking engagement at each station orindex of tool turret 18. If the number of teeth in each coupling can bedivided without a remainder by the number of stations of tool turret 18the teeth of couplings 78, 80 can be urged into interleaved lockingengagement at each station of tool turret 18. Keyways 81 in coupling 26receive keys 28 to secure coupling 26 to tool turret 18. A pin 82 isretained in a blind hole in curvic coupling 26 by a setscrew 84. Pin 82can extend into any one of four locating holes 86 equally spaced atintervals in coupling 32 to provide four positions or stations for toolturret l8. Curvic coupling 32 has a plurality of circumferentiallyspaced coun terbores 88 and keyways 89 to receive capscrews 38 and keys36 (FIG. 2) to secure the coupling to base slide 16. The use of curviccouplings to lock the tool turret to the base provides an extremelyrigid indexing turret structure which reduces tool chatter and vibrationon heavy machining operations.

As shown in FIGS. 2 and 7, locknut 44 is rotated by an actuator bar 90retained for sliding movement by a slot 92 in plug 48 and reciprocatedby a ram of a hydraulic cylinder 94. Cylinder 94 is mounted on base 16and its ram is connected to actuator bar 90 through piston rod 96 and alost-motion connector 98. Actuator bar 90 has a cross slot 100 whichretains for transverse sliding motion a block 102. A pin 104 with aflange on one end is retained in block 102 and is secured to nut 44. PinI64 is free to rotate within block 102 and when actuator bar 90 movesfrom the solid to the phantom line position shown in FIG. 7, block 1102slides transversely to the motion of bar 96 (as shown in FIG. 2) androtates nut 44 to unlock the tool turret. Preferably, the pitch and leadof the threads of sleeve 40 and the depth of the teeth of curviccouplings 26, 32 are selected so that the rotation of nut 44 through anarc of 70 will move tool turret 18 from the locked to the unlockedposition.

When unlocked, tool turret I8 is rotated by gear 66 and a rack I66 shownin FIGS. 3 and 4 retained by a slot 108 in plug 46 to engage gear 66. Asshown in FIGS. 8 and 9, each tooth N6 of rack 1106 is divided into aplurality of segments by longitudinally extending flutes or grooves 118and each tooth 120 of gear 66 is segmented by circumferential flutes orgrooves I222. The segments of teeth I16 and 120 are axially spaced suchthat as shown in FIG. 8 rack 106 can be reciprocated without its teethengaging the teeth of gear 66 when tool turret I6 is locked and as shownin FIG. 9 will engage with the teeth of gear 66 only when the toolturret is axially displaced to the unlocked position. As shown in FIG.2, rack R06 is reciprocated by a ram of a cylinder 1 10 mounted on baseslide 16. The ram of cylinder 110 is connected by rod H2 and lostmotioncoupling 114 to rack 106.

In operating indexing turret l hydraulic cylinder 94 is energized tomove actuating bar 90 downward as viewed in FIG. 2 or from the solidline to phantom position shown in FIG. 7 thereby rotating locking nut 44clockwise (as viewed in FIG. 2). Clockwise rotation of nut 44 axiallyadvances sleeve 40 and tool turret 18 thereby disengaging curviccouplings 26 and 32 as shown in FIGS. 4 and 10 and engaging rack 106 andgear 66 as shown in FIG. 9. Since the teeth of rack 106 and gear 66 areengaged when tool turret 18 is unlocked, energizing cylinder 110 to moverack 106 downward (as viewed in FIG. 2) rotates gear 66 and shaft 50counterclockwise. Rotation of shaft 50 advances or indexes tool turret18 so that a tool 24 is properly positioned with respect to a workpiece.After tool turret 18 has been advanced, cylinder 94 is energized in theopposite direction to move actuating bar 90 upward (as shown in FIG. 2)thereby rotating locknut 44 counterclockwise (as shown in FIG. 2).counterclockwise rotation of locknut 44 axially retracts tool turret l8and urges curvic couplings 26 and 32 into firm locking engagement asshown in FIGS. 3 and 10. Guide pin 82 assures that the curvic couplingsare properly aligned before disengagement of gear 66 and rack 106 andalso that tool turret 18 has been indexed or advanced a whole ratherthan a fraction of a station. Guide pin 82 also prevents scuffing of theteeth of gear 66 and the curvic couplings as they disengage and engage.Locking tool turret E8 in position disengages the teeth of rack 106 andgear 66 (as shown in FIG. 8) so that cylinder 110 can be energized tomove rack 106 either upward or downward (as viewed in FIG. 2) toposition rack 106 to turn tool turret 18 in the proper direction toselect the next station. Preferably, rack 106 is long enough to rotateor index tool turret 18 through all of its stations in a singleunidirectional stroke. With this arrangement tool turret 18 can beadvanced more than one station without momentarily stopping and lockingthe turret at each intermediate station. Also rack 106 can turn toolturret 18 in either direction of rotation to reach the desired station.Thus, the indexing cycle time can be reduced because the path ofrotation containing the least number of intermediate stations can beused and the turret is not momentarily stopped at intermediate stationswhen indexing the tool turret to the desired station. Also, if desired,the tool turret can be unidirectionally indexed.

What is claimed as new is as follows:

1. An indexing turret for a machine tool comprising a base, a toolturret mounted for rotation about and movement along an axis withrespect to said base, detent means and socket means connected to saidbase and said tool turret to lock said base and said tool turret againstrotation with respect to each other when said tool turret is axiallydisplaced along said axis such that said detent means and said socketmeans are engaged; displacement means carried by said base and operablyconnected to said tool turret to axially move said tool turret to afirst position wherein said socket means and detent means are disengagedso that said tool turret is free to rotate and to a second axiallydisplaced position wherein said socket means and said detent means arefirmly engaged so said tool turret is locked against rotation withrespect to said base, and a gear operably connected to said tool turretand axially movable therewith, said gear having a plurality of teeth andat least one circumferential groove through said teeth dividing eachtooth into at least two segments, aNd a rack carried by said base forlongitudinal sliding movement, said rack having a plurality of teeth andat least one longitudinal groove through said teeth dividing each toothinto at least two segments, said gear and said rack being positionedwith respect to each other other such-that said tooth segments aredisengaged when said detent means and socket means are locked inengagement and become. engaged when said tool turret is axially moved sothat said detent means and socket means are disengaged.

2. The indexing turret of claim 1 in which said displacement meanscomprises a nut member and a bolt member each having mating threadsthereon, one of said members connected to said tool turret and the otherof said members carried by said base, and means operably connected toone of said members for rotating it with respect to the other membersuch that rotation of one member with respect to the other in onedirection moves said tool turret axially and urges said detent means andsocket means into locking engagement and rotation in a directionopposite to said one direction moves said tool turret axially anddisengages said detent means and said socket means.

3. The indexing turret of claim 2 in which said last-mentioned means forrotating said members with respect to each other comprises an actuatorbar carried by said base for longitudinal sliding motion therein, saidactuator bar having a generally transverse cross-slide, and a followerblock carried by said cross-slide and operably connected to said onemember such that said one member is rotated by longitudinal movement ofsaid actuator bar.

4. The indexing turret of claim 1 in which said detent means comprises afirst rack having a plurality of teeth thereon and said socket meanscomprises a second rack having a plurality of teeth thereon, said teethof said racks being adapted to mesh with each other when urged into firmengagement to lock said tool turret and said base against rotation withrespect to each other.

5. The indexing turret of claim 4 in which each of said racks comprisesa ring each having a plurality of integral generally axially extendingand circumferentially spaced teeth on one face thereof.

6. The indexing turret of claim 2 in which said detent means comprises afirst rack having a plurality of teeth thereon and said socket meanscomprises a second rack having a plurality of teeth thereon, said teethof said racks being adapted to mesh with each other when urged into firmengagement to lock said tool turret and said base against rotation withrespect to each other.

7. The indexing turret of claim 1 in which said detent means comprises afirst ring having a plurality of generally radially extending andcircumferentially spaced teeth on one face thereof and said socket meanscomprises a second ring having a plurality of radially extending andcircumferentially spaced teeth on one face thereof, said teeth of saidrings being adapted for being urged into meshing engagement to preventrotation of one of said rings with respect to the other of said rings,said displacement means comprises a sleeve coaxial with said tool turretand connected thereto for axial movement therewith and rotation thereto,said sleeve having double lead threads thereon, a locknut carried bysaid base, said locknut having mating threads and threadingly engagingsaid sleeve, and an actuator bar carried by said base for slidinglongitudinal movement generally transverse to the axis of rotation ofsaid tool turret and operably connected with said nut to rotate said nutwith respect to said sleeve, and a shaft extending through and journaledfor free rotation within said sleeve and connected to said tool turretand said gear.

8. An indexing turret for a machine tool comprising a base, a threadednut member carried by said base, a sleeve member carried by said baseand having threads mating with said threads of said nut member, one ofsaid members being adapted for rotary movement with respect to the otherof said members and said sleeve member being adapted for axial movementwith respect to said base in response to rotary movement of said onemember, a tool turret connected to said sleeve member for axial movementtherewith and rotation in relation thereto, detent means and socketmeans connected to said base and said tool turret to lock said base andsaid tool turret against rotation with respect to each other when saidtool turret is axially displaced by said nut and sleeve members on saidaxis such that said detent means and said socket means are engaged andto release said base and said tool turret to be is axially displaced onsaid axis by said nut member and said sleeve member such that saiddetent means and said socket means are disengaged, and a drive shaftcoaxially extending through said sleeve, connected to tool turret, andadapted for rotating said tool turret when said socket means and saiddetent means are disengaged.

9. The indexing turret of claim 8 which also comprises an actuator barcarried by said base for longitudinal sliding motion therein generallytransverse to said axis, a generally transverse cross-slide on saidactuator ban-and a follower block carried by said cross-slide andoperably connected to said one member such that said one member isrotated by longitudinal movement of said actuator bar.

10. The indexing turret of claim 8 which also comprises a gear operablyconnected to said drive shaft and axially movable therewith, said gearhaving a plurality of teeth and at least one circumferential groovethrough said teeth dividing each tooth into at least two segments, and arack carried by said base for longitudinal sliding movement, generallytransverse to said axis, said rack having a plurality of teeth and atleast one longitudinal groove through said teeth dividing each toothinto at least two segments, said gear and said rack being positionedwith respect to each other such that said tooth segments are disengagedwhen said detent means and socket means are locked in engagement andbecome engaged when said tool turret is axially moved so that saiddetent means and socket means are disengaged.

Ill. The indexing turret of claim 8 in which said detent means and saidsocket means comprises first and second racks in the form of a ring eachhaving a plurality of integral, generally radially and axially extendingand circumferentially spaced teeth in one face thereof with the teeth ofsaid racks being adapted to mesh with each other when urged into firmengagement to lock said tool turret and said base against rotation withrespect to each other.

12. The indexing turret of claim 14 in which said detent means and saidsocket means comprises second and third racks in the form of a ring eachhaving a plurality of integral, generally radially and axially extendingand circumferentially spaced teeth in one face thereof with the teeth ofsaid second and third racks being adapted to mesh with each other whenurged into firm engagement to lock said tool turret and said baseagainst rotation with respect to each other.

3 3 I UNHED STATES PATENT OFFICE QERTIFKCATE OF CQRREC'EION Patent No, 3628, 400 Dated December 21, 197].

Inventor(s) Ronald D. Chope and Frank A. gevonkoski It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 3, line 71., cancel ."other" (second occurrence) Column 4, line29, after "generally" insert radially and Column 6, line 13, change "14"to l0 3ig ned and sealed this 2nd day of. May 1972.

Attest:

EDNARDjfiLFLETCHER, JR. ROBERT GOT'I'SGHALK Atc estlng OfficerCommissioner of. Patents

1. An indexing turret for a machine tool comprising a base, a toolturret mounted for rotation about and movement along an axis withrespect to said base, detent means and socket means connected to saidbase and said tool turret to lock said base and said tool turret againstrotation with respect to each other when said tool turret is axiallydisplaced along said axis such that said detent means and said socketmeans are engaged; displacement means carried by said base and operablyconnected to said tool turret to axially move said tool turret to afirst position wherein said socket means and detent means are disengagedso that said tool turret is free to rotate and to a second axiallydisplaced position wherein said socket means and said detent means arefirmly engaged so said tool turret is locked against rotation withrespect to said base, and a gear operably connected to said tool turretand axially movable therewith, said gear having a plurality of teeth andat least one circumferential groove through said teeth dividing eachtooth into at least two segments, aNd a rack carried by said base forlongitudinal sliding movement, said rack having a plurality of teeth andat least one longitudinal groove through said teeth dividing each toothinto at least two segments, said gear and said rack being positionedwith respect to each other other such that said tooth segments aredisengaged when said detent means and socket means are locked inengagement and become engaged when said tool turret is axially moved sothat said detent means and socket means are disengaged.
 2. The indexingturret of claim 1 in which said displacement means comprises a nutmember and a bolt member each having mating threads thereon, one of saidmembers connected to said tool turret and the other of said memberscarried by said base, and means operably connected to one of saidmembers for rotating it with respect to the other member such thatrotation of one member with respect to the other in one direction movessaid tool turret axially and urges said detent means and socket meansinto locking engagement and rotation in a direction opposite to said onedirection moves said tool turret axially and disengages said detentmeans and said socket means.
 3. The indexing turret of claim 2 in whichsaid last-mentioned means for rotating said members with respect to eachother comprises an actuator bar carried by said base for longitudinalsliding motion therein, said actuator bar having a generally transversecross-slide, and a follower block carried by said cross-slide andoperably connected to said one member such that said one member isrotated by longitudinal movement of said actuator bar.
 4. The indexingturret of claim 1 in which said detent means comprises a first rackhaving a plurality of teeth thereon and said socket means comprises asecond rack having a plurality of teeth thereon, said teeth of saidracks being adapted to mesh with each other when urged into firmengagement to lock said tool turret and said base against rotation withrespect to each other.
 5. The indexing turret of claim 4 in which eachof said racks comprises a ring each having a plurality of integralgenerally axially extending and circumferentially spaced teeth on oneface thereof.
 6. The indexing turret of claim 2 in which said detentmeans comprises a first rack having a plurality of teeth thereon andsaid socket meAns comprises a second rack having a plurality of teeththereon, said teeth of said racks being adapted to mesh with each otherwhen urged into firm engagement to lock said tool turret and said baseagainst rotation with respect to each other.
 7. The indexing turret ofclaim 1 in which said detent means comprises a first ring having aplurality of generally radially extending and circumferentially spacedteeth on one face thereof and said socket means comprises a second ringhaving a plurality of radially extending and circumferentially spacedteeth on one face thereof, said teeth of said rings being adapted forbeing urged into meshing engagement to prevent rotation of one of saidrings with respect to the other of said rings, said displacement meanscomprises a sleeve coaxial with said tool turret and connected theretofor axial movement therewith and rotation thereto, said sleeve havingdouble lead threads thereon, a locknut carried by said base, saidlocknut having mating threads and threadingly engaging said sleeve, andan actuator bar carried by said base for sliding longitudinal movementgenerally transverse to the axis of rotation of said tool turret andoperably connected with said nut to rotate said nut with respect to saidsleeve, and a shaft extending through and journaled for free rotationwithin said sleeve and connected to said tool turret and said gear. 8.An indexing turret for a machine tool comprising a base, a threaded nutmember carried by said base, a sleeve member carried by said base andhaving threads mating with said threads of said nut member, one of saidmembers being adapted for rotary movement with respect to the other ofsaid members and said sleeve member being adapted for axial movementwith respect to said base in response to rotary movement of said onemember, a tool turret connected to said sleeve member for axial movementtherewith and rotation in relation thereto, detent means and socketmeans connected to said base and said tool turret to lock said base andsaid tool turret against rotation with respect to each other when saidtool turret is axially displaced by said nut and sleeve members on saidaxis such that said detent means and said socket means are engaged andto release said base and said tool turret to be free to rotate withrespect to each other when said tool turret is axially displaced on saidaxis by said nut member and said sleeve member such that said detentmeans and said socket means are disengaged, and a drive shaft coaxiallyextending through said sleeve, connected to tool turret, and adapted forrotating said tool turret when said socket means and said detent meansare disengaged.
 9. The indexing turret of claim 8 which also comprisesan actuator bar carried by said base for longitudinal sliding motiontherein generally transverse to said axis, a generally transversecross-slide on said actuator bar, and a follower block carried by saidcross-slide and operably connected to said one member such that said onemember is rotated by longitudinal movement of said actuator bar.
 10. Theindexing turret of claim 8 which also comprises a gear operablyconnected to said drive shaft and axially movable therewith, said gearhaving a plurality of teeth and at least one circumferential groovethrough said teeth dividing each tooth into at least two segments, and arack carried by said base for longitudinal sliding movement, generallytransverse to said axis, said rack having a plurality of teeth and atleast one longitudinal groove through said teeth dividing each toothinto at least two segments, said gear and said rack being positionedwith respect to each other such that said tooth segments are disengagedwhen said detent means and socket means are locked in engagement andbecome engaged when said tool turret is axially moved so that saiddetent means and socket means are disengaged.
 11. The indexing turret ofclaim 8 in which said detent means and said socket means comprises firstand second racks in the Form of a ring each having a plurality ofintegral, generally radially and axially extending and circumferentiallyspaced teeth in one face thereof with the teeth of said racks beingadapted to mesh with each other when urged into firm engagement to locksaid tool turret and said base against rotation with respect to eachother.
 12. The indexing turret of claim 14 in which said detent meansand said socket means comprises second and third racks in the form of aring each having a plurality of integral, generally radially and axiallyextending and circumferentially spaced teeth in one face thereof withthe teeth of said second and third racks being adapted to mesh with eachother when urged into firm engagement to lock said tool turret and saidbase against rotation with respect to each other.